Smaller Mean Particle Size Research Articles

Machine learning guided prediction of dynamic energy release in high-entropy alloys

High-entropy alloy (HEA) type energetic structural materials (ESMs) offer exceptional strength, adequate ductility and reactivity upon dynamic loading, thus demonstrating great potentials in pyrotechnic applications. However, the main factors governing their energetic performance remain elusive, primarily attributable to the intricate mechanical-thermal-chemical coupling effects and the inherent challenges of HEA design. To address this, we propose a small-data machine learning framework designed to predict the energetic performance of HEA-type ESMs, employing support vector regression, leave-one-out cross-validation, and principal component analysis (PCA) to effectively manage a small, unevenly distributed, and highly dimensional dataset. Notably, the framework achieved a coefficient of determination (R2) of 0.854 while upholding robust performance, interpretability and computational efficiency. Fracture elongation (εt) and compressive yield strength (σcys) were identified as critical features, with σcys positively influencing performance while both εt and unit theoretical heat of combustion (UTHC) demonstrated negative effect. Guided by the framework, a series of novel Ti-V-Ta-Zr alloys with the comparable UTHC, velocity (v) and weight (m) but tailored εt and σcys were designed and tested. Ti30V30Ta30Zr10 alloy exhibited a commendable balance of mechanical properties and the smallest mean particle size, aligning with the model predictions and suggesting more thorough energy release during ballistic experiments.

An investigation to enhance the performance of molten carbonate-direct coal/carbon fuel cells through improvements in anode layouts and the compositions of carbonate electrolyte

Two anode configurations are systematically tested in composite electrolytes of molten carbonate with Cs2CO3 at various temperatures using different carbon fuels, including bituminous coal, bituminous coal char, carbon black, and graphite powder. The results of electrochemical impedance spectroscopy show that electrolytes composed of (Li-K)2CO3 62:38 doped with 20 wt% Cs2CO3 and utilizing graphite powder as a fuel exhibit reduced ohmic and charge transfer resistance. This can be attributed to the decreased surface tension, which enhances the gas solubility of the reactants within the electrolytic matrix. The analysis of particle size distribution through laser diffraction reveals that the graphite specimen has the smallest mean particle size, resulting in an enhanced rate of electrochemical oxidation. The ultimate and proximate analysis indicates that graphite powder has a lower moisture and ash ratio along with a significantly higher fixed carbon content compared to other carbon fuels. Therefore, the obtained V-j &P-j curves in Anode 1 illustrate that graphite powder yields the highest current density and power density of 903 mA/cm2 and 172 mW/cm2, respectively, at an operating temperature of 680 °C under the laboratory conditions. These values surpass those reported in the existing literature. In contrast, Anode 2 exhibits low performance, due to ash particles regime-controlled at the lower part of the chamber during the coal pyrolysis. Based on results, we suggest that graphite powder is the promising fuel candidate for MC-DCFC to achieve the higher performance.

Impact of Solution Chemistry on the Biotechnological Synthesis and Properties of Palladium Nanoparticles

The biosynthesis of palladium nanoparticles supported on microbial cells (bio-Pd) has attracted much recent interest, but the effect of solution chemistry on the process remains poorly understood. Biological buffers can be used to maintain physiological pH during the bioreduction of Pd(II) to Pd(0) by microbial cells, however, buffer components have the potential to complex Pd(II), and this may affect the subsequent microbe-metal interaction. In this study, a range of Pd(II) salts and biological buffers were selected to assess the impact of the solution chemistry on the rate of bioreduction of Pd(II) by Geobacter sulfurreducens, and the resulting biogenic palladium nanoparticles. The different buffer and Pd(II) combinations resulted in changes in the dominant Pd(II) species in solution, and this affected the amount of palladium recovered from solution by the microbial cells. The physical properties of the bio-Pd nanoparticles were altered under different solution chemistries; only slight variations were observed in the mean particle size (<6 nm), but significant variations in particle agglomeration, the extent of Pd(II) bioreduction and subsequent catalytic activity for the reduction of 4-nitrophenol (4-NP) were observed. The combination of sodium tetrachloropalladate and bicarbonate buffer resulted in bio-Pd with the smallest mean particle size, and the fastest initial rate of reaction for 4-NP reduction (0.33 min–1). Other solution chemistries appeared to damage the cells and result in bio-Pd with relatively poor catalytic performance. This work emphasises that future studies into bio-Pd synthesis should consider the importance of solution chemistry in controlling the speciation of Pd(II) and its impact on both the bioreduction process and the resulting properties of the nanoparticles produced, in order to maximise Pd(II) biorecovery and optimise catalytic properties.

Performance of a rotating packed bed with blade packings in synthesizing nano-sized Fe3O4 particles

Nano-sized Fe3O4 particles were continuously synthesized in the rotating packed bed with blade packings where the rotational speed was set at 1800 rpm, the liquid flow rate of aqueous FeCl2/FeCl3 was kept at 0.5 L/min, and the liquid flow rate of aqueous NaOH was maintained at 0.5 L/min with the chemical co-precipitation route that the synthesis temperature was fixed at 25 °C, the FeCl2 concentration was fixed at 0.15 mol/L, the FeCl3 concentration was fixed at 0.3 mol/L, and the NaOH concentration was fixed at 1.2 mol/L. The average crystallite size and mean particle size of the as-synthesized nano-sized Fe3O4 particles were 12.7 nm and 10.9 nm, respectively. The rate of continuous synthesis of nano-sized Fe3O4 particles was 23.6 kg/day. The as-synthesized nano-sized Fe3O4 particles exhibited a superparamagnetic characteristic at 25 °C. Furthermore, the saturation magnetization of the as-synthesized nano-sized Fe3O4 particles was 66.4 emu/g. The as-synthesized nano-sized Fe3O4 particles had the Type-IV isotherm for N2 adsorption-desorption with a BET specific surface area of 109.4 m2/g. The maximum Orange G adsorption capacity of the as-synthesized nano-sized Fe3O4 particles at 25 °C and pH 3 was 55.0 mg/g. This maximum Orange G adsorption capacity was much higher than that (5.7 mg/g) of the commercial nano-sized Fe3O4 particles that were purchased from Sigma-Aldrich (SA-Fe3O4) because the as-synthesized nano-sized Fe3O4 particles had a smaller mean particle size than SA-Fe3O4. Accordingly, the as-synthesized nano-sized Fe3O4 particles are a promising magnetic adsorbent in the removal of Orange G from water.

Lutein and β-Carotene Characterization in Free and Nanodispersion Forms in Terms of Antioxidant Activity and Cytotoxicity

PurposeCarotenoids are potent natural antioxidants with many important applications. Their nanodispersion formulations can solve problems that may limit their usage. In this study, we produced carotenoid nanodispersions from extracted lutein (nano-Lut), extracted β-carotene (nano-EBc), and synthetic β-carotene (nano-SBC).MethodsThe present study has quantitatively emphasized the physicochemical, antioxidant, and cytotoxic properties of free and nanodispersed formulations of lutein and β-carotene. The nanodispersions were characterized by spectral absorption, dynamic light scattering, and zeta potential. Antioxidant and cytotoxicity assays were conducted for free and their nanodispersed forms. The cytotoxicity of free carotenoids and their nanodispersions was conducted on HSF, VERO, and BNL cell lines.ResultsNano-Lut has the smallest mean particle size (185.2 ± 40.5 nm, PDI of 0.183 ± 0.01, and zeta potential of −28.6 ± 6.4 mV). Nano-SBc showed monomodal size distribution (220.5 ± 30.09 nm, PDI of 0.318 ± 0.03, and zeta potential of −12.1 ± 5.9 mV), while nano-EBc showed a bimodal size distribution (with a mean particle size of 498.3 ± 88.9 nm, PDI of 0.65 ± 0.08, and zeta potential of −39.7 ± 1.3 mV). All prepared nanodispersions showed less than 20% loss during the formulation process. Antioxidant assays showed that extracted lutein was the most active and synthetic β-carotene was the least. Cells showed higher tolerance for lutein and its nanodispersion than extracted or synthetic β-carotene either in free or nanodispersion forms.ConclusionsThe study proved that lutein in nanodispersed form possesses the smallest size, the highest antioxidant activity, and the lowest cytotoxicity among the tested formulations.

Esterified Soy Proteins with Enhanced Antibacterial Properties for the Stabilization of Nano-Emulsions under Acidic Conditions

Soy protein isolate (SPI), including β-conglycinin (7S) and glycinin (11S), generally have low solubility under weakly acidic conditions due to the pH closed to their isoelectric points (pIs), which has limited their application in acidic emulsions. Changing protein pI through modification by esterification could be a feasible way to solve this problem. This study aimed to obtain stable nano-emulsion with antibacterial properties under weakly acidic conditions by changing the pI of soy protein emulsifiers. Herein, the esterified soy protein isolate (MSPI), esterified β-conglycinin (M7S), and esterified glycinin (M11S) proteins were prepared. Then, pI, turbidimetric titration, Fourier transform infrared (FTIR) spectra, intrinsic fluorescence spectra, and emulsifying capacity of esterified protein were discussed. The droplet size, the ζ-potential, the stability, and the antibacterial properties of the esterified protein nano-emulsion were analyzed. The results revealed that the esterified proteins MSPI, M7S, and M11S had pIs, which were measured by ζ-potentials, as pH 10.4, 10.3, and 9.0, respectively, as compared to native proteins. All esterified-protein nano-emulsion samples showed a small mean particle size and good stability under weakly acidic conditions (pH 5.0), which was near the original pI of the soy protein. Moreover, the antibacterial experiments showed that the esterified protein-based nano-emulsion had an inhibitory effect on bacteria at pH 5.0.

Green Biosynthesis of Silver Nanoparticles Using Aqueous Extracts of Ageratum Conyzoides and Their Anti-Inflammatory Effects.

The NLRP3 inflammasome, which plays a central role in innate immunity, is linked to a variety of inflammatory diseases, and thus it may provide a new target for the treatment of those diseases. Biosynthesized silver nanoparticles (AgNPs), particularly those synthesized using medicinal plant extracts, have recently been shown to be a promising therapeutic option. Herein, the aqueous extract of Ageratum conyzoids was used to prepare a series of sized AgNPs (AC-AgNPs), in which the smallest mean particle size was 30 ± 1.3 nm with a polydispersity of 0.328 ± 0.009. The ζ potential value was -28.77 with a mobility of -1.95 ± 0.24 cm2/(v·s). Its main ingredient, elemental silver, accounted for about 32.71 ± 4.87% of its mass, and other ingredients included amentoflavone-7,7⁗-dimethyl ether, 1,3,5-tricaffeoylquinic acid, kaempferol 3,7,4'-triglucoside, 5,6,7,3',4',5'-hexamethoxyflavone, kaempferol, and ageconyflavone B. In LPS+ATP-stimulated RAW 264.7 and THP-1 cells, AC-AgNPs significantly inhibited the release of IL-1β, IL-18, TNF-α, and caspase-1, indicating that AC-AgNPs can inhibit the activation of the NLRP3 inflammasome. The mechanistic study revealed that AC-AgNPs could decrease the phosphorylation levels of IκB-α and p65, resulting in decreased expression of NLRP3 inflammasome-related proteins, including pro-IL-1β, IL-1β, procaspase 1, caspase 1P20, NLRP3, and ASC, and also scavenge the level of intracellular ROS to prevent NLRP3 inflammasome assembly. Furthermore, AC-AgNPs attenuated the in vivo expression of inflammatory cytokines by suppressing NLRP3 inflammasome activation in a peritonitis mouse model. Our study provides evidence that the as-prepared AC-AgNPs can inhibit the inflammatory process by suppressing NLRP3 inflammasome activation and might be used to treat NLRP3 inflammasome-driven inflammatory diseases.

The harnessing of the waste arising from Y-TZP dental ceramics manufactured by CAD/CAM to be used as alternative dental materials

A large amount of yttria-stabilized zirconia (Y-TZP) waste is produced during the manufacture of dental prostheses by the CAD/CAM milling process. This work investigated the recycling and processing of zirconia waste powder (ZWP), generated from the manufacture of dental prostheses (CAD/CAM milling process). The physical and mechanical characteristics of the bodies produced with ZWP were evaluated. The received ZWP was calcined at 500 °C and de-agglomerated with a roll jar mill under different experimental conditions. The grinding condition with a relation between grinding medium mass (GM) and ZWP mass of 13 and a milling time of 90 min presented the best results. This procedure produced ZWP with the smallest mean particle size (0.4 μm) and the lowest tetragonal-monoclinic transformation (16.9%). The water absorption, apparent porosity, bulk density, and mechanical properties were evaluated from ZWP non-deagglomerated and ZWP de-agglomerated after sintering at 1300 °C, 1400 °C, and 1500 °C. ZWP de-agglomerated samples reached bulk density, microhardness, and flexural strength values of 5.8 ± 0.1 g/cm3, 1523 ± 173 HV, and 342.8 ± 66.7 MPa, respectively. The achieved values of bulk density and microhardness were similar to those of commercial ZrO2 bodies processed under the same conditions, 6.0 ± 0.1 g/cm3 and 1412 ± 70 HV, respectively. But flexural strength of ZWP bodies was lower than that of commercial ZrO2, 680.5 ± 96.0 MPa. However, the achieved strength is higher than that observed for porcelain and glass-ceramic dental materials used for single-unit anterior or posterior prostheses (<200 MPa), which depicts the ZWP potential as an alternative low-cost and high-strength material in ceramic prostheses.

CaCO3 loaded lipid microspheres prepared by the solid-in-oil-in-water emulsions technique with propylene glycol alginate and xanthan gum.

Calcium carbonate (CaCO3) is difficult to deliver in food matrices due to its poor solubility. In this work, CaCO3 powders were encapsulated into Solid-in-Oil-in-Water (S/O/W) emulsions to fabricate delivery systems. The impact of the concentrations of propylene glycol alginate and Xanthan gum (PGA-XG) complexes on the physical stability and structural characteristics of S/O/W calcium-lipid emulsions microspheres were studied. The S/O/W calcium-lipid emulsions were characterized by the particle size, zeta potential, physical stability, and apparent viscosity. The S/O/W calcium-lipid emulsion has higher physical stability (including 6-week storage at 4°C), smaller mean particle size (7.60 ± 1.10 μm), and higher negative zeta-potential (45.91 ± 0.97 mV) when the concentration of PGA-XG complexes was 0.8 wt%. Moreover, Confocal laser scanning microscopy (CLSM) images confirmed that the CaCO3 powders were encapsulated in the O phase. Transmission electron microscopy (TEM) showed that S/O/W calcium-lipid emulsion was spherical. The X-ray diffraction (XRD) analysis further confirmed that CaCO3 was loaded in the S/O/W calcium-lipid emulsion as an amorphous state. The formation mechanism of S/O/W calcium-lipid microspheres was studied by Fourier transform infrared spectroscopy (FTIR) and Raman spectrum analysis. This study provided new ideas that accelerate the creation of a novel type of calcium preparation with higher quality utilization.

Powder preparation during ball milling and laser additive manufacturing of aluminum matrix nanocomposites: Powder properties, processability and mechanical property

• Nanocomposite powder for additive manufacturing was economically prepared. • The nanocomposite powder showed near-spherical shape and high flowability. • Nano-TiB 2 particles was uniformly dispersed on the surface of aluminum powder. • The optimal nanocomposite powder exhibited good processability. • The as-fabricated nanocomposite exhibited favorable mechanical property. The additive manufacturing method of laser powder bed fusion (LPBF) has a great potential in producing high-performance metal matrix nanocomposite components. However, nanocomposite powder feasible for LPBF is still limited in availability. In this work, AlSi10Mg powder containing 2 wt% TiB 2 nanoparticles was prepared by ball milling of the constituent powder to meet the following two criteria: (i) a uniform dispersion of nanoparticles on the surface of the micro powder and (ii) a high flowability of the produced nanocomposite powder. The evolution of the powder properties with the milling dose was studied. The results indicated that with the increase of milling dose, the nano-TiB 2 particles were dispersed uniformly but the Al matrix gradually underwent plastic deformation. Under optimized milling conditions, the aluminum matrix nanocomposite powder showed a small mean particle size, narrow size distribution, smooth surface, and a spherical shape with uniformly dispersed nanoparticles. These properties are beneficial for a good LPBF processability. During LPBF process, a favorable forming quality of the optimized nanocomposite powder was evident. A mechanical characterization demonstrated an outstanding tensile strength of ∼ 450 MPa and excellent ductility of ∼ 7.2 % for the built parts.

Oppositely Charged Pickering Emulsion Co-Stabilized by Chitin Nanoparticles and Fucoidan: Influence of Environmental Stresses on Stability and Antioxidant Activity.

Single emulsifiers exhibit varying degrees of restriction in stabilizing emulsions. Oppositely charged chitin nanoparticles and fucoidan complex particles were used as emulsifiers to stabilize a o/w Pickering emulsion and explore its stability and antioxidant activity under different environmental stresses. The results showed that the emulsion with the smallest mean particle size (1.02 μm) and strongest zeta potential (−29.3 mV) was formed at pH 7. Moreover, at this pH, it presented the highest physical stability and antioxidant activity and the lowest emulsion creaming index. The investigation of the effect of temperature on the stability and antioxidant activity of the emulsion revealed that, after freezing/thawing at −20 °C, the emulsion was unstable, the particle size increased, and the stability and antioxidant activity were low. In contrast, the emulsions treated at 25, 37, and 60 °C displayed no significant differences and exhibited high stabilities and antioxidant activities. Additionally, increasing the salt ion concentration further decreased the emulsion stability and antioxidant activity. Particularly, the emulsion with a salt concentration of 500 mM displayed the lowest stability, and stratification occurred after 30 d of storage. The Pickering emulsion remained stable under different environmental stresses expect for at a temperature of −20 °C and 500 mM salt ion concentration.

Fine powders from dyed waste wool as odor adsorbent and coloration pigment

Herein, waste dyed wool was transferred into wool powder (WP) using a mechanical pulverization process. This powder benefits from the rich exposed functional groups and porous structures, which endow WP with capacities to adsorb odor molecules. WP milled for 6 h exhibited improved properties including homogeneous surfaces, small mean particle size (3.63 μm) and increased surface area, contributing to its highest odor ammonia adsorption capacity (2.65 mg g−1) and removal rate (91%) among all tested samples. Loading with WP endows cotton fabrics (CF) with greatly improved deodorizing properties and vivid color. WP-coated CF displayed improved ammonia removal properties compared to pristine CF, achieving 65.71% adsorption rate. The K/S value of WP-coated CF reached 1.844 at o.w.f.% of 15. Coated fabrics also showed stable color fastness to washing. This study paves the way for using powders from waste as both odor adsorbent and coloring pigment for fabric functionalization.

Formulation and Pathohistological Study of Mizolastine-Solid Lipid Nanoparticles-Loaded Ocular Hydrogels.

BackgroundMizolastine (MZL) is a dual-action nonsedating topical antihistamine anti-inflammatory agent that is used to relieve allergic conditions, such as rhinitis and conjunctivitis. Solid lipid nanoparticles (SLNs) are advanced delivery system in ophthalmology, with the merits of increasing the corneal drug absorption and hence improved bioavailability with the objective of ocular drug targeting.MethodsFirst, MZL was formulated as MZL-SLNs by hot homogenization/ultrasonication adopting a 32 full factorial design. Solid-state characterization, in vitro release, and stability studies have been performed. Then, the optimized MZL-SLNs formula has been incorporated into ocular hydrogels using 1.5% w/v Na alginate and 5% w/v polyvinylpyrrolidone K90. The gels were evaluated via in vitro release as well as in vivo studies by applying allergic conjunctivitis congestion in a rabbit-eye model.ResultsThe optimized formula (F4) was characterized by the highest entrapment efficiency (86.5±1.47%), the smallest mean particle size (202.3±13.59 nm), and reasonable zeta potential (−22.03±3.65 mV). Solid-state characterization of the encapsulation of MZL in SLNs was undertaken. In vitro results showed a sustained release profile from MZL-SLNs up to 30 hours with a non-Fickian Higuchi kinetic model. Stability studies confirmed immutability of freeze-dried MZL-SLNs (F4) upon storage for 6 months. Finally, hydrogel formulations containing MZL-SLNs, proved ocular congestion disappearance with completely repaired conjunctiva after 24 hours. Moreover, pretreatment with MZL-SLNs–loaded hydrogel imparted markedly decreased TNF-α and VEGF-expression levels in rabbits conjunctivae compared with post-treatment with the same formula.ConclusionMZL-SLNs could be considered a promising stable sustained-release nanoparticulate system for preparing ocular hydrogel as effective antiallergy ocular delivery systems.

A Simulation Study on the Effect of Particle Size Distribution on the Printed Geometry in Selective Laser Melting

Abstract Selective laser melting (SLM) process is a powder bed fusion additive manufacturing process that finds applications in aerospace and medical industries for its ability to produce complex geometry parts. As the raw material used is in the powder form, particle size distribution (PSD) is a significant characteristic that influences the build quality in turn affecting the functionality and esthetic aspects of the product. This article investigates the effect of PSD on the printed geometry for 316L stainless steel pow der, where three coupled in-house simulation tools based on discrete element method (DEM), computational fluid dynamics (CFD), and structural mechanics are employed. DEM is used for simulating the powder bed distribution based on the different powder PSD. The CFD is used as a virtual testbed to determine thermal parameters such as heat capacity and thermal conductivity of the powder bed viewed as a continuum. The values found as a stochastic function of the powder distribution are used to analyze the effect on the melted zone and deformation using structural mechanics. Results showed that mean particle size and PSD had a significant effect on the packing density, melt pool layer thickness, and the final layer thickness after deformation. Specifically, a narrow particle size distribution with smaller mean particle size and standard deviation produced solidified final layer thickness closest to nominal layer thickness. The proposed simulation approach and the results will catalyze the development of geometry assurance strategies to minimize the effect of particle size distribution on the geometric quality of the printed part.

Optimization of processing parameters to produce nanoparticles prepared by rapid nanoprecipitation of pea starch

Field pea starch was thermally solubilized in water and subsequently ultrasonicated and then used to produce starch nanoparticles (SNPs) via a rapid nanoprecipitation method with the addition of the antisolvent (AS) ethanol into the starch solution (solvent, S). The spherical shape of SNPs with a small mean particle size was visualized by dynamic light scattering (DLS) and field emission-scanning electron microscopy (FE-SEM), which demonstrated a narrow size distribution (PSD) and good water dispersibility. Processing parameters, such as duration and amplitude of ultrasonication, AS/S ratio, starch concentration, separation and drying techniques, were investigated in relation to their effect on SNPs properties. There is an optimal AS/S ratio (1:1) and starch concentration (10 mg/mL) which gives rise to smaller SNPs with a narrower PSD. The formation of SNPs was found to follow a kinetically controlled nucleation-growth/aggregation mechanism in which amylose molecules formed the initial critical nuclei. The ultrasonication amplitude and separation and drying techniques significantly affected the size and morphology of SNPs. Moderate shear facilitated rapid starch aggregation and SNPs precipitation, enabling easy recovery by centrifugation and subsequent freeze drying. The freeze-dried SNPs were able to be dispersed quickly to form a SNP suspension in Milli-Q water. The dispersed SNPs showed good thermal stability in water and retained their particle characteristics at a temperature range of 25–60 °C. Further research exploring the potential of these SNPs as nutraceutical carriers for applications in both health and nutrition industries is warranted.

Performance analysis and comparison of methyl-modified Al2O3/SiO2 xerogels fabricated by two methods

Abstract Two methyl-modified Al2O3/SiO2 xerogels, i. e. AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels, were prepared using aluminum isopropoxide and aluminum nitrate nonahydrate as the aluminum precursors, respectively. The appearance, density, viscosity, Gibbs activation energy for viscous flow and reaction rate constant of the sols were analyzed and compared. Their microstructures were characterized by means of powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and nitrogen adsorption–desorption measurements. The results show that the Al–O–Si bond is formed in the AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels. The ANN-Al2O3/MSiO2 sol has a smaller mean particle size and greater sol stability than the AIP-Al2O3/MSiO2 sol. Meanwhile, the ANN-Al2O3/MSiO2 xerogel has a smaller pore size and higher porosity. The total pore volume and specific surface area of the ANN-Al2O3/MSiO2 xerogel are 27.27% and 29.36% larger than those of the AIP-Al2O3/ MSiO2 sample, respectively. The saturated adsorption capacity of the ANN-Al2O3/MSiO2 xerogel to methylene blue is 7.15% larger than that of the AIP-Al2O3/MSiO2 xerogel.

Physicochemical changes and age gelation in stored UHT milk: Seasonal variations

The physicochemical changes and the occurrence of age gelation during the storage of indirect UHT milk produced in different seasons in New Zealand were examined. UHT milk produced in the early season had the lowest protein and calcium contents, the smallest mean particle size when fresh, and the lowest propensity for age gelation. During storage, the changes in pH, ionic calcium concentration, particle size, and protein profiles of the milk and serum did not vary greatly between the seasons. Protein analysis indicated that the Maillard reaction and limited proteolysis occurred during the storage of UHT milk. The heat-induced aggregation among partially κ-casein-depleted casein micelles might play a part in the physicochemical gelation of UHT milk during storage.

Effect of temperature, pH, and ionic strength on the structure and physical stability of double emulsions prepared with starch

To developed stable double emulsions (DEs) that were resistant to environmental stress, native corn starch (NCS) or high-amylose starch was used as material to prepare starch-based double emulsions (SDEs). The effects of temperature (4–60 °C, pH 7.0, 0 mmol/L NaCl), pH (2.0–8.0, 25 °C, 0 mmol/L NaCl), and NaCl concentration (10–100 mmol/L, 25 °C, pH 7.0) on the droplet size distribution, particle size, microstructure, interfacial rheology, and interfacial tension of the SDEs were evaluated. Results revealed that DEs stabilized by NCS of 7 g/100 mL concentration (7% NCS DEs) had the small mean particle size (4.80 ± 0.56 μm) with type-A structure, a high elasticity (14.98 Pa) and toughness (132.85 Pa) interfacial film. Moreover, the relationship between the different SDEs structures and their physical stability confirmed that 7%NCS DE exhibited excellent physical stability and was resistant to heat, acid and alkali conditions, and salt, owing to their dense network structure (Tanδ<1) and stable interfacial tension (39.85 ± 0.03 mN/m). This study demonstrates the potential of SDEs provides new practical applications.

Mixed micelles for enhanced oral bioavailability and hypolipidemic effect of liquiritin: preparation, in vitro and in vivo evaluation

Objectives Liquiritin, as one of the main flavonoids in Glycyrrhiza, exhibits extensive pharmacological effects, such as the anti-oxidant, anti-inflammatory, anti-tumor and so on. Herein, the aqueous solubility and oral bioavailability of liquiritin was purposely enhanced via the preparation of the mixed micelles. Methods The liquiritin-loaded micelles (LLM) were fabricated via thin-film dispersion method. The optimal LLM formulation was evaluated through physical properties including particle size (PS), encapsulation efficiency (EE) and drug loading (DL). In vitro accumulate release as well as in vivo pharmacokinetics were also evaluated. Moreover, the hypolipidemic activity of LLM was observed in the hyperlipidemia mice model. Results The LLM exhibited a homogenous spherical shape with small mean PS, good stability and high encapsulation efficiency. The accumulate release rates in vitro of the LLM were obviously higher than free liquiritin. The oral bioavailability of the formulation was heightened by 3.98 times in comparison with the free liquiritin. More importantly, LLM increased the hypolipidemic and effect of alleviating lipid metabolism disorder in hepatocytes of liquiritin in hyperlipidemia mice model. Conclusions Collectively, the improved solubility of liquiritin in water coupled with its enhanced oral bioavailability and concomitant hypolipidemic activity could be attributed to the incorporation of the drug into the mixed micelles.

Celecoxib Loaded In-Situ Provesicular Powder and Its In-Vitro Cytotoxic Effect for Cancer Therapy: Fabrication, Characterization, Optimization and Pharmacokinetic Evaluation.

Introduction: Several recent studies have shown that the role of cyclooxygenase 2 (COX-2) in carcinogenesis has become more evident. It affects angiogenesis, apoptosis, and invasion, and plays a key role in the production of carcinogens. It has also been reported that COX-2 inhibitors such as celecoxib (CLX) might play an effective role in preventing cancer formation and progression. Formulation of CLX into nanovesicles is a promising technique to improve its bioavailability and anticancer efficacy. Aim: The aim of this study is to optimize and evaluate the anticancer efficacy of CLX-loaded in-situ provesicular powder composed of surfactants and fatty alcohol-based novel nanovesicles in-vitro and determine its pharmacokinetic parameters in-vivo. Methods: The novel provesicular powders were prepared by the slurry method and optimized by 32 full factorial design using the desirability function. Results: Small mean particle size was achieved by the formed vesicles with value of 351.7 ± 1.76 nm and high entrapment efficacy of CLX in the formed vesicles of 97.53 ± 0.84%. Solid state characterization of the optimized formulation showed that the powder was free flowing, showed no incompatibilities between drug and excipients and showed smooth texture. The cytotoxic study of the optimized formula on HCT-116, HepG-2, A-549, PC-3 and MCF-7 cell lines showed significant increase in activity of CLX compared to its free form. The pharmacokinetic study on albino rabbits after oral administration showed significant increase in the area under the curve (AUC)0–24 h and significantly higher oral relative bioavailability of the optimized formulation compared to Celebrex® 100 mg market product (p < 0.05). Conclusion: All findings of this study suggest the potential improvement of efficacy and bioavailability of CLX when formulated in the form of in-situ provesicular powder composed of surfactants and fatty alcohol-based novel nanovesicles for its repositioned use as an anticancer agent.